The present invention relates generally to vascular infusion systems and components, including catheter assemblies and devices used with catheter assemblies. In particular, the present invention relates to systems and methods for increasing the rigidity and snag-resistance of a catheter tip of a vascular infusion system having catheter hole arrays to provide enhanced infusion flow rates, lower system pressures, and reduced catheter exit jet velocities. Additionally, the present invention relates to improving the overall rigidity of a thin-walled structure.
Vascular access devices are used for communicating fluid with the anatomy of a patient. For example, vascular access devices, such as catheters, are commonly used for infusing fluid, such as saline solution, various medicaments, and/or total parenteral nutrition, into a patient, withdrawing blood from a patient, and/or monitoring various parameters of the patient's vascular system.
A variety of clinical circumstances, including massive trauma, major surgical procedures, massive burns, and certain disease states, such as pancreatitis and diabetic ketoacidosis, can produce profound circulatory volume depletion. This depletion can be caused either from actual blood loss or from internal fluid imbalance. In these clinical settings, it is frequently necessary to infuse blood and/or other fluid rapidly into a patient to avert serious consequences.
Additionally, the ability to inject large quantities of fluid in a rapid manner may be desirable for certain other medical and diagnostic procedures. For example, some diagnostic imaging procedures utilize contrast media enhancement to improve lesion conspicuity in an effort to increase early diagnostic yield. These procedures necessitate viscous contrast media be injected by a specialized “power injector” pump intravenously at very high flow rates, which establishes a contrast bolus or small plug of contrast media in the bloodstream of the patient which results in enhanced image quality.
Power injection procedures generate high pressures within the infusion system, thereby requiring specialized vascular access devices, extension sets, media transfer sets, pump syringes, and bulk or pre-filled contrast media syringes. As the concentration (and thereby viscosity) and infusion rate of the contrast media are increased, bolus density also increases resulting in better image quality via computed tomography (CT) attenuation. Therefore, a current trend in healthcare is to increase the bolus density of the contrast media by increasing both the concentration of the contrast media and the rate at which the media is infused into the patient, all of which ultimately drives system pressure requirements higher.
Intravenous infusion rates may be defined as either routine, generally up to 999 cubic centimeters per hour (cc/hr), or rapid, generally between about 999 cc/hr and 90,000 cc/hr (1.5 liters per minute) or higher. For some diagnostic procedures utilizing viscous contrast media, an injection rate of about 1 to 10 ml/second is needed to ensure sufficient bolus concentration. Power injections of viscous media at this injection rate produce significant back pressure within the infusion system that commonly results in a failure of the infusion system components.
Traditionally, rapid infusion therapy entails the use of an intravenous catheter attached to a peristaltic pump and a fluid source. A patient is infused as a tip portion of the catheter is inserted into the vasculature of a patient and the pump forces a fluid through the catheter and into the patient's vein. Current rapid infusion therapies utilize a catheter and catheter tip with geometries identical to those used with traditional, routine infusion rates. These geometries include a tapering catheter tip such that the fluid is accelerated as the fluid moves through the catheter tip and exits into a patient's vasculature. This acceleration of the infused fluid is undesirable for several reasons.
For example, the tapered catheter results in a greater backpressure for the remainder of the catheter assembly. This effect is undesirable due to the limitations of the pumping capacity of the infusion pump as well as the limited structural integrity of the components and subcomponents of the infusion system. For example, if the backpressure becomes too great, the pump's efficiency may decrease and certain seals or connections within the infusion system may fail. Additionally, the fluid acceleration in the catheter tip results in a recoil force that may cause the catheter tip to shift within the patient's vein thereby displacing the catheter and/or damaging the patient's vein and/or injection site. Fluid acceleration also increases the jet velocity of the infusant at the tip of the catheter. In some procedures, the fluid jet may pierce the patient's vein wall thereby leading to extravasation or infiltration. Not only is this uncomfortable and painful to the patient, but infiltration may also prevent the patient from receiving the needed therapy.
To overcome undesirable backpressures and increased acceleration of infused fluids, some intravascular systems include arrays of diffuser holes provided in and around the tip portion of the intravenous catheter. Examples of arrays of diffuser holes and diffuser hole geometries are provided in U.S. patent application Ser. Nos. 12/427,633 and 13/022,501, each of which are incorporated herein by reference.
In general, diffuser holes increase the surface area of the catheter tip opening thereby decreasing fluid pressure at the catheter tip opening. However, addition of diffuser holes at or near the tip of a catheter also reduces the buckling resistance of the catheter thereby making the catheter tip more susceptible to crushing during insertion. As a result, the addition of diffuser holes may result in failed catheterization and physical pain to the patient. Further, addition of diffuser holes provides the catheter with a non-continuous outer surface that may snag or catch on the opening of the patient's skin and/or vein through which the catheter is inserted. This too may result in failed catheterization, physical pain and/or physical damage to the patient.
Thus, while methods and systems currently exist to reduce exit velocity of an infusant during rapid infusion procedures, challenges still exist. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques.